Tests: purge settings cache

Some tests need to change settings, but since MemoryCacheSettingsRepository caches settings in-memory, those changes aren't reflected. The new `purgeSettingsCache` removes it from the container, eliminating that cache.

For UserTest, we also need to regenerate the display name driver, since that's set statically on boot, before we'll get a change to clear the settings cache.

tests/integration/extenders/UserTest.php

@@ -12,6 +12,7 @@ namespace Flarum\Tests\integration\extenders;
 use Flarum\Extend;
 use Flarum\Tests\integration\RetrievesAuthorizedUsers;
 use Flarum\Tests\integration\TestCase;
+use Flarum\Tests\integration\UsesSettings;
 use Flarum\User\DisplayName\DriverInterface;
 use Flarum\User\User;
 use Illuminate\Support\Arr;
@@ -19,6 +20,7 @@ use Illuminate\Support\Arr;
 class UserTest extends TestCase
 {
     use RetrievesAuthorizedUsers;
+    use UsesSettings;
 
     /**
      * @inheritDoc
@@ -37,6 +39,17 @@ class UserTest extends TestCase
         ]);
     }
 
+    /**
+     * Purge the settings cache and reset the new display name driver.
+     */
+    protected function recalculateDisplayNameDriver()
+    {
+        $this->purgeSettingsCache();
+        $container = $this->app()->getContainer();
+        $container->forgetInstance('flarum.user.display_name.driver');
+        User::setDisplayNameDriver($container->make('flarum.user.display_name.driver'));
+    }
+
     protected function registerTestPreference()
     {
         $this->extend(
@@ -51,6 +64,7 @@ class UserTest extends TestCase
     public function username_display_name_driver_used_by_default()
     {
         $this->app();
+        $this->recalculateDisplayNameDriver();
 
         $user = User::find(1);
 
@@ -68,6 +82,7 @@ class UserTest extends TestCase
         );
 
         $this->app();
+        $this->recalculateDisplayNameDriver();
 
         $user = User::find(1);